摘要
全氟和多氟烷基化合物(perfluoroalkyl and polyfluoroalkyl substances,PFAS)作为新污染物,因其环境持久性与生物毒性对水环境构成严重威胁。而河流-地下水交互带中PFAS迁移与滞留特性尚不明确,需要揭示河水水位波动条件下PFAS在交互带中的迁移与滞留机制,厘清PFAS迁移与滞留的关键控制参数。以全氟辛酸(perfluorooctanoic acid,PFOA)为典型污染物,首先基于土柱试验构建一维PFOA迁移模型,验证模型可靠性并反演吸附系数;继而构建二维河流-地下水断面模型,模拟PFOA在交互带中的运移过程及其对不同参数(波高、波长、吸附系数、渗透系数、入渗补给系数、孔隙度)的响应。研究表明:河水水位变化驱动的交互带蓄水效应显著延长了PFOA在交互带中的滞留时间,呈现“易进难出”的非对称迁移特征;与保守溶质相比,PFOA因吸附作用滞留更久;吸附系数、波高、波长和渗透系数是影响PFOA迁移与滞留的关键参数;吸附系数增大显著降低峰值浓度但同时大幅延长滞留时间,波高增大促使峰值升高与滞留时间延长,波长增加会延迟峰值到达时间并延长滞留时间,渗透系数提高可提升PFOA迁移速率并缩短滞留时间。相关成果可为季节性水位波动区域PFAS污染的风险评估与治理提供理论依据。
Perfluoroalkyl and polyfluoroalkyl substances(PFAS),as emerging contaminants,pose a serious threat to aquatic environments due to their environmental persistence and biological toxicity.However,the transport and retention behaviors of PFAS within river-groundwater interaction zones remain poorly understood.Elucidating the mechanisms governing PFAS migration and retention under fluctuating river stage conditions,as well as identifying the key controlling parameters is therefore essential.Perfluorooctanoic acid(PFOA)was selected as a representative PFAS compound.A one-dimensional PFOA transport model was first developed based on soil column experiments to verify model reliability and to inversely estimate the adsorption coefficient.Subsequently,a two-dimensional river-groundwater cross-sectional model was constructed to simulate PFOA transport within the interaction zone and to evaluate its sensitivity to multiple parameters,including fluctuation amplitude,wavelength,adsorption coefficient,hydraulic conductivity,infiltration recharge coefficient,and porosity.River stage fluctuations induce a pronounced storage effect within the interaction zone,significantly prolonging PFOA residence time and producing an asymmetric transport behavior characterized by easy entry but difficult release.Compared with conservative solutes,PFOA exhibits substantially longer retention due to adsorption processes.The adsorption coefficient,fluctuation amplitude,wavelength,and hydraulic conductivity were identified as the dominant factors controlling PFOA migration and retention.An increase in the adsorption coefficient markedly reduces peak concentrations while substantially extending retention time.Greater fluctuation amplitude leads to higher peak concentrations and longer retention,whereas longer wavelengths delay peak arrival and further prolong retention.Higher hydraulic conductivity enhances contaminant transport rates and shortens retention time.These findings provide a theoretical basis for risk assessment and remediation of PFAS contamination in rivergroundwater systems subject to seasonal water-level fluctuations.
作者
许诗滢
谢月清
强郁城
孙媛媛
付融冰
吴吉春
XU Shiying;XIE Yueqing;QIANG Yucheng;SUN Yuanyuan;FU Rongbing;WU Jichun(Key Laboratory of Earth Surficial Geochemistry of Ministry of Education,School of Earth Sciences and Engineering,Nanjing University,Nanjing,Jiangsu 210023,China;College of Environmental Science and Engineering,State Key Laboratory of Pollution Control and Resources Reuse,Tongji University,Shanghai 200092,China)
出处
《水文地质工程地质》
北大核心
2026年第2期223-234,共12页
Hydrogeology & Engineering Geology
基金
国家重点研发课题(2023YFC3707700)。
关键词
全氟辛酸
河流
地下水
交互带
数值模拟
水位波动
perfluorooctanoic acid
river
groundwater
interaction zone
numerical modeling
water level fluctuation
